Mounting for outboard motors



E. c. KIEKHAEFER 3,062,173

MOUNTING FOR OUTBOARD MOTORS Nov. 6, 1962 5 611122! C. Kiekhaefer v i BY Kind/us Star/ e Nov. 6, 1962 E. c. KIEKHAEFER MOUNTING FOR OUTBOARD MOTORS 2 Sheets-Sheet 2 Filed June 6, 1960 INVENTOR.

2 a a w h. kfiw k5 K mm C u 4 Y ms 6 United States Fatent Ofihce 3,062,173 MOUNTING FOR OUTBOARD MOTORS Elmer Carl Kiekhaefer, Cedarhurg, Wis., assignor, by

mesne assignments, to Kiekhaefer Corporation, Chicago, IlL, a corporation of Delaware Filed June 6, 1960, Ser. No. 34,231 7 Claims. (Cl. 115-.-18)

The present invention relates generally to a mounting for outboard mounted power sources and particularly relates to a mounting for power sources constructed with an unusually long drive shaft.

In the conventional mounting for outboard motors, as well as other types of outboard power sources, the motor is mounted in pendant fashion to the boat sternboard by a clamp bracket and swivel bracket assembly carried at the upper end of the motor drive shaft housing. Below the brackets, the housing depends free of the boat and supports the usual under-water propulsion unit on its lower end.

With a mount of this type, the drive shaft housing serves incidentally as a lever or moment arm for the propulsion unit such that the thrust delivered by the propulsion unit is multiplied through the housing to impose upon the latter, the support brackets, and the boat proper substantial dynamic stresses. In the case of an outboard motor having and unusually long drive shaft housing, such as for a boat with a relatively high transom, the resultant stresses are correspondingly increased, and may reach objectionable and sometimes critical proportions.

Under these cirucmstances and in the interest of maintaining the motor weight and expense at a minimum, the conventional mounting is modified to include a lower mount secured to the outer side of the transom in position to engage the drive shaft housing adjacent the lower end thereof. The lower mount is designed to absorb and transmit directly all or substantially all of the thrust of the propulsion unit to the boat to thereby prevent transmission of the thrust lengthwise of the housmg.

The present invention is directed to a new and improved construction for such a lower mount member and which, in addition to its primary objective of absorb.- ing the thrust of the propulsion unit, is designed to reduce frictional resistance between the engaging surfaces of the drive shaft housing and the mount to permit relatively free turning movement of the motor about its, steering axis. For this purpose, a pair of vertical rollers. are mounted on the leading, lower edge of the housing for rotation relative thereto about axes parallel with the steering axis of the motor. The housing rollers are adapted to bear against a concavely curved, vertically dis.- posed race formed on the rearward face of the mount with the race comprising a section of a cylinder whose axis coincides with the steering axis of the motor.

The invention provides a mount which acts to dampen vibrations emanating in the motor to prevent excessive vibration of the boat proper.

In accordance with this aspect of the invention, the mount is constructed of an inner component secured rigidly. to the transom and an outer or drive shaft engaging component assembled together in resilient relation.

Additional vibration dampening is effected by constructing the rollers of the drive shaft housing with a sleeve of resilient material interposed between the outer bearing surface of the rollers and the central axial shaft thereof.

The accompanying drawings illustrate the best mode presently contemplated of carrying out the invention.

In the drawings:

te ted ov- 6. .962

FIG. 1 is an elevational side view of an outboard motor embodying the lower mount of the present invention and which is shown attached to a boat in section;

FIG. 2 is an enlarged fragmentary side elevation of the mount of FIG. 1;

FIG. 3 is a perspective view of the mount of FIG. 2 with parts being broken away and sectioned for the sake of clarity; and

FIG. 4 is a sectional view along lines 4--4 of FIG. 2 with the phantom lines indicating the motor in a turned position and without the boat.

The drawings illustrate an outboard motor 1 having a relatively long drive shaft housing 2 disposed intermediate the power head 3 and the submersible propulsion unit 4. Motor 1 is particularly adapted for use with a boat 5 having a relatively high or deep transom 6 such as shown generally and schematically in FIG. 1.

Motor 1 is mounted to transom 6 by a clamp bracket 7 and swivel bracket 8 pivotally assembled on the trans verse pivot pin 9 to provide for vertical tilting movement of the motor between an operative and inoperative posi: tion. Swivel bracket 8 is pivotally connected to motor 1 by the swivel pin assembly 10 to provide a vertical steering axis 11 for the motor.

A pair of upper resilient mounts 12 (only one shown) and a pair of intermediate resilient mounts 13 (only one shown) are secured to drive shaft housing 2. Mounts 12 and 13 are connected to swivel pin assembly 10 by the mounting bolts 14,

In accordance with the present invention, an addirtional mount indicated generally at '15 in the drawings is secured to the outer lower central portion of transom 6 in alignment with the drive shaft housing 2 with the motor disposed in its normal running position.

Generally, mount 15 constitutes an abutment engaged by the shaft housing 2 immediately above propulsion unit 4 to absorb and transmit directly to the boat all or substantially all the thrust of the propulsion unit and to reduce substantially the length of the lever or moment arm through which the thrust is free to act. The mount of the invention thus substantially reduces the level of operating stresses occurring in the housing, the bracket means securing the motor to the boat, and the boat proper.

With reference to FIGS. 2-4, the mount includes an angle bracket 16 formed integrally and having an angularly disposed wall 17 adapted to fit against the boat transom 6, a horizontal wall 18, and a reinforcing web 19, extending diagonally between the walls. Bracket 16, is secured to transom 6 by a pair of bolts 20 inserted through the openings 21 in bracket wall 17, with horizontal wall 18 and web 19; extending rearwardly from the. transom:

The mount includes also a saddle 22 which is sup.- ported transversely on bracket wall 18 with the saddle ends 23 depending downwardly on either side of the wall. The saddle is adjustably secured to the bracket by a pair of bolts 24 extending through the intermediate portion of the saddle and selectively through one of a plurality of pairs of openings 25 contained in bracket wall 18. The distance between the saddle 22 and the transom 6 may thus be varied to adapt the mount for use with transoms of varying angles.

The. bracket and saddle provide suitable supporting structure for the outer, drive shaft engaging assembly 26 of the mount comprising generally a pair'of capplates 27 and a central plate-like housing 28 for supporting the cap plates. Housing 28 is formed with a pair of spaced side flanges 29 which are turned arcuately inwardly at a cor responding end and along a common center of curvature to define a concave bearing race 30. A reinforcing. rib 31 is formed integrally with the housing and extends be a. tween side flanges 29 along race 30, generally intermediate and normal of the flanges and the race.

Side flanges 29 of housing 28 are tapered outwardly in conicoidal fashion in proceeding from race-3t? and are dished arcuately inwardly between the longitudinal edges thereof to define a semi-cylindrical depression 32 extending substantially the length of the flanges.

Cap plates 27 are tapered conicoidally in the manner of flanges 29 and provided with a longitudinal depression 33 of reverse curvature to that of the flanges 29. Suit able tapped openings 34 are provided in the mating marginal portions 35 of housing flanges 29 and cap plates 27 to receive the bolts 36' to secure the cap plates to the housing, thereby providing a pair of cylindrical sockets 37 in the assembly. The assembly also includes a rigid, metal ring 38 seated generally centrally in each of the sockets in a circumferential groove formed therein.

As shown in FIG. 2, assembly 26 is connected to saddle 22 immediately rearwardly thereof by the mounting bolts 39 which are inserted rearwardly through the rounded and bored extremities of saddle ends 23. Bolts 39 extend axially of sockets 37 and axially through ring 33 in radially spaced relation thereto, and to a point adjacent the rear end of the sockets. Ring 38 and bolt 39 are elastically connected by a resilient rubber sleeve 40 fitted about bolt 39 rearwardly of saddle end 23. The central portion of sleeve 40 is enlarged radially to conform generally to the inside diameter of the ring 38. Sleeve 40 is held captive on bolt 39 by a lock washer 41 and nut 42 disposed on the threaded end of the bolt and is expanded into firm engagement with ring 38 by suitable tightening of the nut.

The rubber sleeve insulates the saddle from the drive shaft engaging assembly to thereby dampen vibrations emanating from the motor proper and prevent their transmission through mount to the boat. The damping effect of the sleeve depends on the extent of its compression and may be varied within limits by adjusting nut 42 relative to bolt 39.

Drive shaft housing 2 is adapted to engage against race 30 through a pair of vertically disposed rollers 43 rotatably supported on the leading edge of the housing in the vertically spaced projections 44 cast integrally with the housing.

Each roller 43 is preferably comprised of a central shaft 45, a rubber sleeve 46 disposed coaxially the length of shaft 45, and an outer bearing ring 47 of metal tightly encircling the radially expanded, central portion of sleeve 46. The roller construction provides additional damping of motor vibrations in the region of the mount.

In accordance with the invention, the rollers are designed to rotate or ride freely on race 39 as motor 1 is turned on its steering axis 11 by constructing the race with a cent-er of curvature corresponding to the motor steering axis 11.

This construction permits the operator to swing the motor through its full steering arc with a minimum of efiort even when the motor is at full throttle.

While adapted for use with all outboard mounted power sources, the mount of the invention is particularly adapted for use with power sources having a long drive shaft wherein the thrust of the propulsion unit, if free to act through the major portion of the drive shaft housing, would subject the power source and its supporting brackets to stresses of substantial proportions.

It is to be noted also that in a mounting of the type discussed herein, the lower mount or abutment is subjected to rather substantial impact loads arising from motor movement thereagainst from a kicked-up or rearward position relative to its horizontal pivot axis. As is known, the impact frequently reaches very substantial proportions under certain conditions and constitutes a serious source of damage to the boat, the motor support brackets and the motor.

The structure of the present invention is extremely advantageous in this respect as the rubber insulation between the mount components supplemented by the resilient rollers on the motor drive shaft housing serve to dampen the impact and reduce proportionately the resulting load on the impacting members.

Various modes of carrying out the invention are contemplated within the scope of the following claims particularly pointing out and distinctly claiming the subject matter regarded as the invention.

I claim:

1. in an outboard mounted power source supported on the transom of a boat for turning movement relative thereto about a vertical steering axis and having a substantially vertical drive shaft housing carrying an underwater propulsion unit at its lower end, the combination of at least one roll-er rotatably mounted on the lower, leading edge of said drive shaft housing for rotation relative thereto about an axis parallel with the steering axis of said power source, and a lower mount secured to said transom and having a rearwardly facing, inwardly curved bearing race disposed to engage the roller on said drive shaft housing to absorb the major portion of the thrust of said underwater propulsion unit, said bearing race comprising a section of a cylinder having an axis coincident with the steering axis of said power source to permit ready turning movement of said power source relative to said race.

2. In an outboard motor mounted to the sternboard of a boat for turning movement relative thereto about a vertical steering axis and comprising generally a power head, an underwater propulsion unit, and an intermediate drive shaft housing connecting said power head and propulsion unit: the combination of a pair of rollers mounted on the lower leading edge of said drive shaft housing for rotation relatively thereto about axes paralleling the steering axis of said motor; and a mount comprising a bracket secured to the rear wall of said transom adjacent the lower portion thereof and projecting rearwardly and horizontally from said transom to provide a supporting member, a saddle disposed transversely on said supporting member, means for adjustably securing said saddle and bracket whereby the saddle may be moved relatively toward or away from said transom, a drive shaft housing engaging assembly provided with a pair of spaced sockets and an inwardly curved race disposed intermediately of said sockets, a rigid ring seated within each of said sockets, mounting bolts extending rearwardly from opposite ends of said saddle and axially within said sockets in coaxially spaced relation to said rings, an elastomeric sleeve disposed on said bolts rearwardly of said saddle and enlarged radially intermediate the ends thereof, means for holding said sleeve captive on said bolt and for expanding the sleeve into tight engagement with said bolt and ring to elastically connect said saddle to said drive shaft housing engaging assembly with said race disposed to engage the rollers on said drive shaft housing to absorb substantially all the thrust of the propulsion unit, and said race having a center of curvature coincident with the steering axis of the motor to facilitate turning movement of the motor about its steering axis.

3. The structure of claim 2 wherein the rollers on said drive shaft housing are comprised of an inner shaft, an elastomeric sleeve disposed coaxially the length of the shaft and having a radially expanded center portion, and an outer annular ring disposed concentrically about the central portion of said sleeve, said shaft, sleeve and ring being rotatable as a unit.

4. In an outboard mounted power source supported on the transom of a boat for turning movement relative thereto about a vertical steering axis and having a substantially vertical drive shaft housing carrying an underwater propulsion unit at its lower end: the combination of at least one roller mounted on the lower, leading edge of said drive shaft housing for rotation relative thereto about an axis parallel with the steering axis of said power source, said roller comprising a central shaft, a sleeve of resilient material extending coaxially the length of said shaft, and an outer rigid ring disposed concentrically on said sleeve, said ring, sleeve and shaft being rotatable as a unit; and a lower mount secured to said transom and having a rearwardly facing, inwardly curved bearing race disposed to engage the roller on said drive shaft housing to absorb the major portion of the thrust of said underwater propulsion unit, said bearing race comprising a section of a cylinder having an axis coincident with the steering axis of said power source to permit ready turning movement of said power source relative to said race.

5. In an outboard mounted power source supported on the transom of a boat for turning movement relative thereto about a vertical steering axis and having a substantially vertical drive shaft housing carrying an underwater propulsion unit at its lower end, the combination of at least one roller mounted on the lower, leading edge of said drive shaft housing for rotation relative thereto about an axis parallel with the steering axis of said power source, and a lower mount secured to said transom and having an outer portion formed with a rearwardly facing, inwardly curved bearing race disposed to engage the roller on said drive shaft housing to absorb the major portion of the thrust of said underwater propulsion unit and a separate and distinct inner portion secured to said transom and to said outer portion through vibration damping means, said bearing race on said outer portion comprising a section of a cylinder having an axis coincident with the steering axis of said power source to permit ready turning movement of said power source relative to said race.

6. In a mount for a dirigible outboard propulsion unit for boats, means pivotally suspending the unit from the sternboard of a boat to provide for vertical tilting movement of the unit, separate abutment means secured to the boat sternboard near the bottom of the boat and having a rearwardly facing arcuate bearing surface concentric with the vertical steering axis of said unit, and roller means rotatably mounted on the leading edge of said unit for rollably engaging said bearing surface of said abutment means to provide direct transmission of the thrust of said unit to said boat in substantially all positions of dirigibility of said unit thereby reducing the lever forces upon said first named means resulting from the thrust of said unit.

7. The construction of claim 6 in which a cushion dampening means is provided for the thrust forces transmitted to the boat through said abutment means.

References Cited in the file of this patent UNITED STATES PATENTS 902,853 Betz NOV. 3, 1908 2,209,301 Johnson v July 23, 1940 2,723,639 Hinrichs Nov. 15, 1955 

